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Poly(N-isopropylacrylamide) in aqueous solution undergoes a phase transition at approximately 32 degrees C. The fluorescence properties of benzofurazans are affected by solvent polarity. We combine these two characteristics for the first time to develop sensitive fluorescent molecular thermometers. Five fluorescent monomers having a benzofurazan skeleton were synthesized, and the copolymers of N-isopropylacrylamide (NIPAM) and a small quantity of the fluorescent monomer were obtained to investigate their fluorescence properties. With increase in temperature, the copolymers in water showed the temperature-induced phase transition at approximately 32 degrees C and the fluorescence intensities of the copolymers concurrently increased. Especially, for the copolymer of 4-N-(2-acryloyloxyethyl)-N-methylamino-7-N,N-dimethylaminosulfonyl-2,1,3-benzoxadiazole and NIPAM, the fluorescence intensity at 37 degrees C was 13.3-fold that seen at 29 degrees C. The sensitive range of temperature of these fluorescent molecular thermometers is changed by the replacement of the NIPAM units by N-isopropylmethacrylamide or N-n-propylacrylamide units in the copolymers. The basis of these fluorescent molecular thermometers is the decrease in the microenvironmental polarities near the main chains of the copolymers with increasing temperature, as confirmed from the maximum emission wavelengths of the benzofurazan units in the copolymers. The responses from the copolymers to the change in temperature are reversible and exactly repeatable during at least 10 cycles of heating and cooling.

Spruce wood charcoal, macadamia shell charcoal, coal activated carbon, and coconut shell activated carbon catalyze the gasification of organic compounds in supercritical water. Feedstocks studied in this paper include glycerol, glucose, cellobiose, whole biomass feedstocks (depithed bagasse liquid extract and sewage sludge), and representative Department of Defense (DoD) wastes (methanol, methyl ethyl ketone, ethylene glycol, acetic acid, and phenol). The effects of temperature, pressure, reactant concentration, weight hourly space velocity, and the type of catalyst on the gasification of glucose are reported. Complete conversion of glucose (22% by weight in water) to a hydrogen-rich synthesis gas was realized at a weight hourly space velocity (WHSV) of 22.2 h-1 in supercritical water at 600 °C, 34.5 MPa. Complete conversions of the whole biomass feeds were also achieved at the same temperature and pressure. The destruction efficiencies for the representative DoD wastes were also high. Deactivation of the carbon catalyst was observed after 4 h of operation without swirl in the entrance region of the reactor, but the carbon gasification efficiency remained near 100% for more than 6 h when a swirl generator was employed in the entrance of the reactor.

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Two references cited in the text were omitted from the Literature Cited: Reddy, S.; Aggarwal, B. B. Curcumin is a non-competitive and selective inhibitor of phosphorylase kinase. FEBS Lett. 1994, 341, 19-22. Yamamoto, H.; Hanada, K.; Kawasaki, K.; Nishijima, M. Inhibitory effect of curcumin on mammalian phos-pholipase D activity.

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The effect of temperature (390−450 °C) and residence time (0.5−10 s) at a pressure of 25 MPa was investigated for lignin conversion in supercritical water (SCW) using a continuous flow apparatus designed to rapidly heat the system to the desired reaction temperature. Conversion of lignin in SCW occurs rapidly, and complete depolymerization can be achieved within a 5 s residence time. A high degree of depolymerization is achieved from rapid heating to supercritical temperatures. In addition, supercritical conditions result in a high yield of solid that does not significantly change with an increase in temperature or residence time. To test the suggested hypothesis that the formation of low molecular weight fragments and cross-linking of these fragments forms higher molecular weight fragments, the yield of char, gaseous products, phenolic compounds (phenol, guaiacol, catechol, o-cresol, m-cresol, and catechol) and aromatic hydrocarbons (benzene, toluene, and naphthalene) were determined. The formation of phenolic compounds at short residence time indicates that ether bonds in lignin are easily degraded under supercritical conditions. A reaction network model was proposed, and the subsequent kinetic parameters for the conversion pathways were determined by assuming a first-order reaction. It is observed that the rate constant of overall lignin conversion obeys Arrhenius behavior. The individual rate constants of each reaction in the network are evaluated to determine conformity to Arrhenius behavior.

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